1、Designation: E 1086 94 (Reapproved 2005)Standard Test Method forOptical Emission Vacuum Spectrometric Analysis ofStainless Steel by Point-to-Plane Excitation Technique1This standard is issued under the fixed designation E 1086; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method2covers for the optical emissionvacuum spect
3、rometric analysis of stainless steel in solid formby the point-to-plane excitation technique for the followingelements in the concentration ranges shown:Element Concentration Range, %Chromium 17.0 to 23.0Nickel 7.5 to 13.0Molybdenum 0.01 to 3.0Manganese 0.01 to 2.0Silicon 0.01 to 0.90Copper 0.01 to
4、0.30Carbon 0.005 to 0.25Phosphorus 0.003 to 0.15Sulfur 0.003 to 0.0651.2 This test method is designed for the routine analysis ofchill-cast disks or inspection testing of stainless steel samplesthat have a flat surface of at least 13 mm (0.5 in.) in diameter.The samples must be sufficiently massive
5、to prevent overheat-ing during the discharge and of a similar metallurgical condi-tion and composition as the reference materials.1.3 Analytical curves are plotted using the concentrationratio method as shown in Practice E 158. One or more of thereference materials must closely approximate the compo
6、sitionof the specimen. The technique of analyzing reference mate-rials along with unknowns and performing the indicatedmathematical corrections may also be used to correct forinterference effects and to compensate for errors resulting frominstrument drift.Avariety of such systems are commonly used.A
7、ny of these that will achieve analytical accuracy equivalent tothat reported for this test method are acceptable.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate sa
8、fety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 158 Practice for Fundamental Calculations to ConvertIntensities into
9、 Concentrations in Optical Emission Spec-trochemical Analysis4E 172 Practice for Describing and Specifying the ExcitationSource in Emission Spectrochemical Analysis4E 305 Practice for Establishing and Controlling Spectro-chemical Analytical CurvesE 406 Practice for Using Controlled Atmospheres in Sp
10、ec-trochemical AnalysisE 876 Practice for Use of Statistics in the Evaluation ofSpectrometric Data4E 1060 Practice for Interlaboratory Testing of Spectro-chemical Methods of Analysis43. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E 135.4. Summary
11、of Test Method4.1 A controlled discharge is produced between the flatsurface of the specimen and the counter electrode. The radiantenergy of selected analytical lines are converted into electricalenergies by photomultiplier tubes and stored on capacitors. Thedischarge is terminated at a predetermine
12、d level of accumu-lated radiant energy from the internal standard iron line or aftera fixed exposure time. At the end of the exposure period, thecharge on each capacitor is measured, and displayed orrecorded as a relative energy or concentration.1This test method is under the jurisdiction of ASTM Co
13、mmittee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.01 on Iron, Steel, and Ferroalloys.Current edition approved Jan. 1, 2005. Published March 2005. Originallyapproved in 1985. Last previous edition approved in 2000 as E 1086
14、94 (2000).2Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: E02-1023.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
15、e information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 The chemical composition of stainless steels must bedetermined accur
16、ately in order to ensure the desired metallur-gical properties. This procedure is suitable for manufacturingcontrol and inspection testing.6. Apparatus6.1 Sample Preparation Equipment:6.1.1 Sample Mold, capable of producing castings that arehomogeneous and free of voids and porosity. The followingmo
17、ld types have been found to produce acceptable samples.6.1.1.1 Refractory Mold Ring, having a minimum insidediameter of 32 mm (1.25 in.) and a minimum height of 25 mm(1.0 in.). The ring is placed on a flat surface of a copper plateapproximately 50 mm (2.0 in.) thick.6.1.1.2 Book-Type Steel Mold, to
18、produce a chill-cast disk64 mm (2.5 in.) in diameter and 13 mm (0.5 in.) thick. The wallthickness of the mold should be 32 mm (1.25 in.) to aid chillcasting.6.1.2 Abrasive Grinder, a suitable belt grinder, horizontaldisk grinder, or similar grinding apparatus. The resultingsurface should be uniforml
19、y plane and free of defects. Thesemay be either wet or dry grinding devices. Grinding materialswith grit sizes ranging from 60 to 180 have been foundsatisfactory.6.2 Excitation Source, with parameters capable of produc-ing a usable spectrum in accordance with 10.2 and PracticeE 172.6.3 Excitation St
20、and, suitable for mounting in optical align-ment, a flat surface of the specimen in opposition to a counterelectrode. The stand shall provide an atmosphere of argon andmay be water cooled. Electrode and argon are described in 7.1and 7.2.6.4 Spectrometer, having sufficient resolving power andlinear d
21、ispersion to separate clearly the analytical lines fromother lines in the spectrum of a specimen in the spectral region170.0 to 500.0 nm. Spectrometer characteristics for two of theinstruments used in this test method are described as havingdispersion of 0.697 nm/mm (first order), the focal length o
22、f 1m. Spectral lines are listed in Table 1.6.5 Measuring System, consisting of photomultiplier tubeshaving individual voltage adjustment, capacitors on which theoutput of each photomultiplier tube is stored and an electronicsystem to measure voltages on the capacitors either directly orindirectly, a
23、nd the necessary switching arrangements to pro-vide the desired sequence of operation.6.6 Readout Console, capable of indicating the ratio of theanalytical lines to the internal standard with sufficient precisionto produce the accuracy of analysis desired.6.7 Vacuum Pump, capable of maintaining a va
24、cuum of 25m Hg.6.8 Flushing System, consisting of argon tanks, a pressureregulator, and a gas flowmeter. Automatic sequencing shall beprovided to actuate the flow of argon at a given flow rate for agiven time interval and to start the excitation at the end of therequired flush period. The flushing s
25、ystem shall be in accor-dance with Practice E 406.NOTE 1It is not within the scope of this test method to prescribe alldetails of equipment to be used. Equipment varies among laboratories.7. Reagents and Materials7.1 Argon, either gaseous or liquid, must be of sufficientpurity to permit proper excit
26、ation of the analytical lines ofinterest. Argon of 99.998 % purity has been found satisfactory.Refer to Practice E 406.7.2 Electrodes, may be 3 to 6 mm (0.125 to 0.25 in.) indiameter ground to a 90 tip or whatever the instrumentmanufacturer recommends for the particular source. Hard-drawn, fine, sil
27、ver rods, thoriated-tungsten rods, or othermaterial may be used provided it can be shown experimentallythat equivalent precision and accuracy are obtained.8. Reference Materials8.1 Certified Reference Materials are available from theNational Institute of Standards and Technology5and otherinternation
28、al certification agencies.8.2 Reference Materials with matrices similar to that of thetest specimen and containing varying amounts of the elementsto be determined may be used provided they have beenchemically analyzed in accordance with ASTM standard testmethods. These reference materials shall be h
29、omogeneous, andfree of voids or porosity.8.3 The reference materials shall cover the concentrationranges of the elements being sought. A minimum of threereference materials shall be used for each element.5National Institute of Standards and Technology, U.S. Department of Com-merce, Gaithersburg, MD
30、20899.TABLE 1 Analytical and Internal Standard LinesElement Wavelength, nmConcentration Switch OverPointsChromium 298.919Nickel 243.789227.021218.549216.910Molybdenum 202.030 1 %369.265Manganese 293.306Silicon 251.612A288.158Copper 327.396 0.10 %Carbon 193.092Phosphorus 178.287ASulfur 180.731IronB27
31、1.441322.706ASilicon 251.612 can have a small but significant interference from molybde-num 251.611. Phosphorus 178.287 may show small but significant interferencesfrom unlisted lines or background due to molybdenum, chromium, and manga-nese. Interference corrections will not be necessary if: separa
32、te silicon andphosphorus curves are used for 316 and 317 alloys; the manganese content variesonly between 0.7 and 1.5 %; and the chromium concentration is held between 17and 20 %.BEither iron line 271.441 or 322.775 with narrow entrance and exit slits to avoidinterference from manganese 322.809 can
33、be used as internal standard with anyof the listed analytical lines. Iron 271.441 is not appropriate for tungsten tool steelsor super alloys with high cobalt because of interference from cobalt 271.442.E 1086 94 (2005)29. Preparation of Samples9.1 Cast samples from molten metal into a suitable molda
34、nd cool. Prepare the surface to be analyzed on a suitable beltor disk grinder. Prepare the surface of the specimens andreference materials in a similar manner. If wet surfacingprocedure is used, dry the specimens for proper excitation inthe argon atmosphere.10. Excitation and Exposure10.1 Be certain
35、 the spectrometer is in optical alignment andhas been calibrated in accordance with the instructions of themanufacturer.10.2 Electrical ParametersTwo different types of sourceswere employed in the testing of this test method.10.2.1 Directional Self-Initiating Capacitor DischargeSource:Capacitance, F
36、 0.015Inductance, L1, H 310Inductance, L2,H 20Resistance, V residualPotential, V 13 500Peak Current, A 90First Valley Current, A 60Current pulse duration, s 120Number of discharges/s 24010.2.1.1 Exposure Conditions:Flush, s 7 Argon Flow 0.42 m3/hPreburn, s 20 Argon Flow 0.42 m3/hIntegration, s 20 Ar
37、gon Flow 0.42 m3/h10.2.2 Triggered Capacitor Discharge Source:Preburn ExposurePulse Output:Capacitance, F (d-c charged) 7.5 2.5Inductance, H 50 50Resistance, V residual residualPotential, V 950 950Peak Current, A 275 100Current pulse duration, s 250 130Number of discharges/s 120 120Trigger:Capacitan
38、ce (d-c charged), F 1.2 .Inductance, H residual .Resistance, V residual .Potential, V 425 .10.2.2.1 Exposure Conditions:Flush, s 2 Argon Flow 0.56 m3/hPreburn, s 10 Argon Flow 0.56 m3/hExposure, s 10 or 15 Argon Flow 0.56 m3/h11. Calibration, Standardization, and Verification11.1 CalibrationUsing th
39、e conditions given in 10.2, ex-cite calibrants and potential standardants in a random se-quence, bracketing these burns with excitations of any mate-rials intended for use as verifiers. (A verifier may be used as acalibrant even though it is burned only as a verifier.) Thereshall be at least three c
40、alibrants for each element, spanning therequired concentration range. Repeat with different randomsequences at least four times. Follow the procedure for theconcentration-ratio method in accordance with Practice E 158.Using the averages of the data for each point, determineanalytical curves in accor
41、dance with Practice E 305.11.2 StandardizationFollowing the manufacturers rec-ommendations, standardize on an initial setup or anytime thatit is known or suspected that readings have shifted. Make thenecessary corrections either by adjusting the controls on thereadout or by applying arithmetic corre
42、ctions. Standardizationwill be done anytime verification indicates that readings havegone out of statistical control.11.3 VerificationShall be done at least at the beginning ofa work shift. Analyze verifiers in replicate to confirm that theyread within expected confidence interval, in accordance wit
43、h11.4.11.3.1 Check the verification after standardizing. If confir-mation is not obtained, run another standardization or investi-gate why the instrument is malfunctioning.11.3.2 Repeat the verification at least every4horiftheinstrument has been idle for more than 1 h. If readings are notin conforma
44、nce, repeat the standardization.11.4 The confidence interval will be established from ob-servations of the repeatability of the verifiers and determiningthe confidence interval for some acceptable confidence level inaccordance with Practice E 876 or by establishing the upperand lower limit of a cont
45、rol chart in accordance with ASTMManual MNL7.6The latter is the preferable approach since italso monitors the consistency of the statistics of the measure-ments and provides a way of maintaining a record of perfor-mance.12. Procedure for Excitation and Radiation Measurement12.1 Produce and record th
46、e spectra using the conditions in10.2.12.2 Replicate ExposureMake duplicate exposures ofeach specimen and report the average. Place the freshlysurfaced specimen on the excitation stand in a manner to effecta gas-tight seal and adequate argon flushing. Position thespecimen so there will be a uniform
47、pattern of excitationsaround its face. For example, a disk-shaped specimen shouldhave a ring of excitation marks around its outer edge andapproximately 6 mm (0.25 in.) from the edge. Avoid the centerof cast specimens because there is more chance of quenchcracks and segregation. Make a good electrica
48、l ground. Coolthe specimen after two excitations to prevent overheating, ifrequired. Examine the specimen after each excitation to evalu-ate the quality of excitation. Cracks, voids, pits, moisture, orinclusions will limit the sampling and the accuracy of adetermination. Successive excitations shall
49、 be sufficientlyseparated so that the discharge patterns do not overlap.13. Calculation of Results13.1 Average the readings obtained for each specimen. Ifthe readout is not in direct concentration units, use this value toobtain the concentrations from the curves, or related scalevalues and concentration by reference to a table that has beenpreviously prepared.6MNL 7 Manual on Presentation of Data and Control Chart Analysis, ASTMManual Series, ASTM International, 6th edition, 1990.E 1086 94 (2005)314. Precision and Bias214.1 PrecisionThe precision of this test me
